* doc/invoke.texi (Spec Files): Document getenv spec function.

[pf3gnuchains/gcc-fork.git] / gcc / doc / gty.texi

diff --git a/gcc/doc/gty.texi b/gcc/doc/gty.texi
index d43feca..ed677c6 100644 (file)
--- a/gcc/doc/gty.texi
+++ b/gcc/doc/gty.texi
@@ -1,4 +1,4 @@
-@c Copyright (C) 2002, 2003, 2004
+@c Copyright (C) 2002, 2003, 2004, 2007
 @c Free Software Foundation, Inc.
 @c This is part of the GCC manual.
 @c For copying conditions, see the file gcc.texi.
@@ -61,7 +61,7 @@ static GTY(()) int @var{counter};        /* @r{save counter in a PCH} */
 @end smallexample
 
 The parser understands simple typedefs such as
-@code{typedef struct @var{tag} *@var{name};} and 
+@code{typedef struct @var{tag} *@var{name};} and
 @code{typedef int @var{name};}.
 These don't need to be marked.
 
@@ -282,6 +282,16 @@ The routine @code{ggc_marked_p} can be used to determine if an element
 has been marked already; in fact, the usual case is to use
 @code{if_marked ("ggc_marked_p")}.
 
+@findex mark_hook
+@item mark_hook ("@var{hook-routine-name}")
+
+If provided for a structure or union type, the given
+@var{hook-routine-name} (between double-quotes) is the name of a
+routine called when the garbage collector has just marked the data as
+reachable. This routine should not change the data, or call any ggc
+routine. Its only argument is a pointer to the just marked (const)
+structure or union.
+
 @findex maybe_undef
 @item maybe_undef
 
@@ -291,6 +301,19 @@ this field is always @code{NULL}.  This is used to avoid requiring
 backends to define certain optional structures.  It doesn't work with
 language frontends.
 
+@findex nested_ptr
+@item nested_ptr (@var{type}, "@var{to expression}", "@var{from expression}")
+
+The type machinery expects all pointers to point to the start of an
+object.  Sometimes for abstraction purposes it's convenient to have
+a pointer which points inside an object.  So long as it's possible to
+convert the original object to and from the pointer, such pointers
+can still be used.  @var{type} is the type of the original object,
+the @var{to expression} returns the pointer given the original object,
+and the @var{from expression} returns the original object given
+the pointer.  The pointer will be available using the @code{%h}
+escape.
+
 @findex chain_next
 @findex chain_prev
 @item chain_next ("@var{expression}")
@@ -411,21 +434,13 @@ header file that should be included in the source file you just changed.
 The file will be called @file{gt-@var{path}.h} where @var{path} is the
 pathname relative to the @file{gcc} directory with slashes replaced by
 @verb{|-|}, so for example the header file to be included in
-@file{objc/objc-parse.c} is called @file{gt-objc-objc-parse.c}.  The
+@file{cp/parser.c} is called @file{gt-cp-parser.c}.  The
 generated header file should be included after everything else in the
 source file.  Don't forget to mention this file as a dependency in the
 @file{Makefile}!
 
-@item
-If a new @file{gt-@var{path}.h} file is needed, you need to arrange to
-add a @file{Makefile} rule that will ensure this file can be built.
-This is done by making it a dependency of @code{s-gtype}, like this:
-@verbatim
-gt-path.h : s-gtype ; @true
-@end verbatim
 @end enumerate
 
 For language frontends, there is another file that needs to be included
 somewhere.  It will be called @file{gtype-@var{lang}.h}, where
 @var{lang} is the name of the subdirectory the language is contained in.
-It will need @file{Makefile} rules just like the other generated files.